Abstract
The neuroradiological considerations about the site of lesions and pathomechanisms of classical aphasic syndrome caused by brain infarction were discussed. In this paper, I gave case studies of some aphasic patients with lesion in the left frontal lobe, with lesion producing conduction aphasia, and with borderzone infarction. (1) The cases of aphasia with left frontal lobe. The patient of pure word dumbness showed the infarction of the precentral gyrus. The aphasic patients who have the lesion of Broca's area presented transcortical sensory aphasia. Motor aphasia occurred with the lesion including both Broca's area and precentral gyrus. Transcortical motor aphasia was observed next to the lesions surrouding Broca's area, or medial portion of the frontal lobe which was perfused by anterior cerebral artery. (2) The site of lesion producing conduction aphasia. The lesion producing conduction aphasia is located mainly in supramarginal gyrus. The lesion of the postcentral gyrus has also the possibility of producing conduction aphasia. (3) The clinical significance of borderzone infarction. Superficial borderzone infarction may cause transcortical aphasia. Anterior type borderzone infarction will produce transcortical motor aphasia, and the case of the posterior type may present transcortical sensory aphasia. Deep borderzone infarction due to left caroid artery occlusion may produce severe aphasia. The marked reduction of cerebral blood flow and metabolism in the left cerebral hemisphere will be observed in these cases.
